Grounding switch

Abstract

The earthing switch (50) comprises a fixed contact (53) installed in a tank (51) filled with insulating gas, and a movable contact (54) installed in the tank (51) so as to be movable between a closing position and a breaking position. The fixed contact (53) comprises a fixed contactor (531). The movable contact (54) comprises a movable contactor (541) that is inserted into the fixed contactor (531) at the closing position and comes into contact with the fixed contactor (531), a first puffer chamber (571) into which insulating gas flows from a hole formed in one end (541a) of the movable contactor (541) that is closer to the fixed contactor (531) during breaking operation, and a second puffer chamber (572) that sprays insulating gas toward the fixed contactor (531) during breaking operation.

Description

[Technical Field]

[0001] The present disclosure relates to a grounding switch incorporated in a gas-insulated switchgear. [Background technology]

[0002] The earthing switchgear incorporated in the gas-insulated switchgear uses a structure in which the moving contact is driven linearly or rotary to perform the breaking and making operations. For example, a suction puffer system is used in which the puffer chamber expands with the opening operation by linear drive, sucking the insulating gas from the tank into the puffer chamber, and the gas flow of the insulating gas sucked into the puffer chamber cools the arc.

[0003] Patent Document 1 discloses a switchgear that forms a gas flow by sucking gas into a puffer chamber during an interruption operation, and extinguishes the arc by blowing the gas flow onto the arc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 5-66852 Summary of the Invention [Problem to be solved by the invention]

[0005] When upgrading the equipment rating of a gas-insulated switchgear, the current to be interrupted during the interruption operation becomes higher voltage, which increases the arc generation time and arc distance. Therefore, the higher the voltage of the current to be interrupted in the earthing circuit breaker, the wider the electrode gap between the moving contact and the fixed contact must be. Thus, in order to enable the earthing switch to interrupt high-voltage current, the earthing switch must be made larger.

[0006] In the switchgear disclosed in Patent Document 1, the direction in which the arc generated between the fixed contact and the movable contact extends is nearly parallel to the direction of the gas flow formed by sucking gas into the puffer chamber, so the effect of the gas flow in extending the arc is small. Therefore, even if the structure of the switchgear disclosed in Patent Document 1 is applied to an earthing switch incorporated in a gas-insulated switchgear, there is a problem that an increase in the size of the earthing switch is unavoidable if the arc generation time and arc distance when breaking current in a breaking operation become long.

[0007] The present disclosure has been made in view of the above, and aims to provide a grounding switch that is capable of interrupting high-voltage current while suppressing an increase in the size of the device. [Means for solving the problem]

[0008] To solve the above-mentioned problems and achieve the object, the earthing switch according to the present disclosure includes a fixed contact installed in a tank filled with insulating gas, a movable contact installed in the tank so as to be movable between a make position where it contacts the fixed contact and a break position where a gap exists between the fixed contact and the movable contact, and an operating device installed outside the tank for causing the movable contact to perform a make operation and a break operation. The fixed contact includes a fixed contactor connected to an electric circuit conductor. The movable contact includes a movable contactor that is inserted into and contacts the fixed contactor at the make position, a first puffer chamber into which insulating gas from the tank flows through a hole formed in one end of the movable contactor closest to the fixed contact during a break operation, and a second puffer chamber that sprays insulating gas toward the fixed contactor during a break operation. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to obtain an earthing switch that is capable of interrupting high-voltage current while suppressing an increase in the size of the device. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a diagram showing the configuration of a gas-insulated switchgear incorporating a grounding switch according to a first embodiment. [Figure 2] 1 is a cross-sectional view taken along the central axis of a movable contact of a grounding switch according to a first embodiment; [Figure 3] Partial cross-sectional view of a grounding switch according to embodiment 1 [Figure 4] FIG. 1 is a diagram showing a gas flow generated during an interruption operation of a grounding switch according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A grounding switch according to an embodiment will be described in detail below with reference to the drawings.

[0012] Embodiment 1 FIG. 1 is a diagram showing the configuration of a gas-insulated switchgear incorporating a grounding switch according to a first embodiment. The gas-insulated switchgear 100 includes an electric circuit 10, a disconnecting switch 20, a circuit breaker 30, a lightning arrester 40, and a grounding switch 50, all of which are installed on the electric circuit 10. When the disconnecting switch 20 and the circuit breaker 30 are closed, they each constitute part of the electric circuit 10. The circuit breaker 30 has an interrupting function for interrupting current during normal operation and fault current. When interrupting the current flowing through the electric circuit 10, the circuit breaker 30 is first set to an interrupted state, and then the disconnecting switch 20 is set to an interrupted state. When a voltage exceeding a preset protection voltage is applied to the electric circuit 10, the lightning arrester 40 releases the charge of the electric circuit 10 to earth, thereby protecting the electric circuit 10 and each device installed on the electric circuit 10.

[0013] Fig. 2 is a cross-sectional view taken along the central axis of a movable contact of a grounding switch according to embodiment 1. Fig. 3 is a partial cross-sectional view of a grounding switch according to embodiment 1. Fig. 3 corresponds to a cross-sectional view taken along line III-III in Fig. 2. A grounding switch 50 includes a tank 51 filled with insulating gas, a fixed contact 53 installed in the tank 51 and installed on an electric circuit conductor 52 that forms a part of an electric circuit 10, a movable contact 54 installed in the tank 51 so as to be movable between a closing position in which the movable contact 53 comes into contact with the fixed contact 53 and a breaking position in which a gap exists between the movable contact 54 and the fixed contact 53, and an operating device 55 installed outside the tank 51 to cause the movable contact 54 to perform a closing operation and a breaking operation.

[0014] The fixed contact 53 includes a fixed contact element 531 and a shield 532 surrounding the fixed contact element 531. The fixed contact element 531 is not limited to a particular shape as long as it has a shape that allows the movable contact element 541 to be inserted when the movable contact 54 is in the closed position. For example, the fixed contact element 531 may be cylindrical as shown in Figures 2 and 3, or may be configured by arranging thin plates with a width of about 4.5 mm in an annular shape.

[0015] The movable contact 54 includes a movable contactor 541 that is linearly driven during closing and opening operations, a cylinder 542 connected to the movable contactor 541, and an anchor 543 that secures the cylinder 542 to the tank 51. The movable contactor 541 has a single-tube portion 561 that is arranged on the side that contacts the fixed contactor 531, and a double-tube portion 562 that is arranged on the side that connects to the cylinder 542. The end of the single-tube portion 561 forms a ring portion 561a. The ring portion 561a is made of a material with a high melting point, such as tungsten. The movable contactor 541 has a structure in which the single-tube portion 561 and the double-tube portion 562 are connected in the axial direction via a connecting portion 565. Therefore, the end of the single cylinder portion 561 farther from the double cylinder portion 562 becomes one end 541a of the movable contactor 541, and the end of the double cylinder portion 562 farther from the single cylinder portion 561 becomes the other end 541b of the movable contactor 541. The inner cylinder 562a is longer than the outer cylinder 562b. Therefore, the end of the inner cylinder 562a farther from the single cylinder portion 561 becomes the other end 541b of the movable contactor 541. A piston 563 is provided at the other end 541b of the movable contactor 541.

[0016] The space inside the inner cylinder 562a is connected to the space inside the single cylinder portion 561 to form a first puffer chamber 571. A guide member 58 made of an insulating material is installed in the single cylinder portion 561. The guide member 58 is fixed with a nut 561c to a support leg 561b provided on the single cylinder portion 561, and is supported with a gap formed between the guide member 58 and the ring portion 561a. The gap between the guide member 58 and the ring portion 561a faces the other end portion 541b side rather than a direction perpendicular to the axial direction.

[0017] A cylinder 542 is disposed between an inner cylinder 562a and an outer cylinder 562b, thereby connecting the movable contact 541 and the cylinder 542 in an expandable and contractible manner. A head portion 542a is formed on the end of the cylinder 542 that is inserted between the inner cylinder 562a and the outer cylinder 562b. The cylinder 542 has a smaller inner diameter only at the head portion 542a. Therefore, a gap is formed between the inner cylinder 562a and the cylinder 542 in the area other than the head portion 542a, forming a space. Therefore, the space between the inner cylinder 562a and the outer cylinder 562b is separated by the head portion 542a into a space on one end 541a side and a space on the other end 541b side.

[0018] A hole 562c is formed in the inner cylinder 562a. Therefore, the space between the inner cylinder 562a and the outer cylinder 562b, which is closer to the other end 541b than the head portion 542a, is connected to the first puffer chamber 571 via the hole 562c.

[0019] The space between the inner cylinder 562a and the outer cylinder 562b, on the one end 541a side of the head portion 542a, forms a second puffer chamber 572. The connecting portion 565 has a gas hole 567 formed therein.

[0020] A seal 563a is provided on the outer periphery of the piston 563, and the gap between the cylinder 542 and the piston 563 is hermetically sealed. Seals 542b and 542c are provided on the outer and inner peripheries of the head portion 542a, respectively, and the gap between the cylinder 542 and the inner cylinder 562a and the gap between the cylinder 542 and the outer cylinder 562b are hermetically sealed.

[0021] A flange 59 is connected to the outer cylinder 562b. A rod 551 that transmits the driving force generated by the operating device 55 is connected to the flange 59. The driving force generated by the operating device 55 is transmitted to the outer cylinder 562b via the rod 551 and the flange 59, whereby the movable contact 541 moves between a break position where it is out of contact with the fixed contact 531 and a close position where it is in contact with the fixed contact 531.

[0022] As described above, the earthing switch 50 according to embodiment 1 has a disconnecting section in insulating gas, which is composed of a fixed contact 53 and a movable contact 54, and the movable contact 54 has a linear drive structure equipped with a first puffer chamber 571 and a second puffer chamber 572 for current interruption.

[0023] 4 is a diagram showing a gas flow generated during an interruption operation of the earthing switch according to the first embodiment. FIG. 4 illustrates only the fixed contact piece 531 and the movable contact 54 of the fixed contact 53, and does not illustrate other parts. During an interruption operation of the earthing switch 50, the movable contact piece 541 moves in a direction away from the fixed contact piece 531. In FIG. 4, the direction of movement of the movable contact piece 541 during an interruption operation is indicated by arrow A. When the movable contact piece 541 moves away from the fixed contact piece 531, an arc 60 is generated between the fixed contact piece 531 and the movable contact piece 541. Because the outer diameter of the movable contact piece 541 is smaller than the inner diameter of the fixed contact piece 531, the arc 60 is generated in a state inclined with respect to the central axis AX of the movable contact piece 541 such that the arc 60 approaches the central axis AX of the movable contact piece 541 as it approaches the movable contact piece 541.

[0024] Furthermore, when the earthing switch 50 is opened, a gas flow is formed by the insulating gas flowing into the first puffer chamber 571 through the gap between the ring portion 561a and the guide member 58. In FIG. 4, the flow of insulating gas flowing into the first puffer chamber 571 through the gap between the ring portion 561a and the guide member 58 is indicated by arrow B. Because the gap between the guide member 58 and the ring portion 561a faces the other end 541b rather than the direction perpendicular to the axial direction, the flow of insulating gas flowing into the first puffer chamber 571 flows in a direction inclined with respect to the central axis of the movable contact 541 so as to approach the central axis of the movable contact 541 as it approaches the one end 541a. Therefore, the flow of insulating gas flowing into the first puffer chamber 571 flows in a direction intersecting with the arc 60. The insulating gas flowing into the first puffer chamber 571 flows in a direction intersecting the arc 60, which increases the effect of extending the arc 60, thereby improving the current interruption performance.

[0025] Furthermore, when the movable contact 54 is opened, the insulating gas in the second puffer chamber 572 is compressed, and a gas flow of the insulating gas is ejected from the gas hole 567. In Fig. 4, the gas flow of the insulating gas ejected from the second puffer chamber 572 through the gas hole 567 is indicated by arrow C. The gas flow ejected from the second puffer chamber 572 proceeds along the single-walled cylindrical portion 561 toward the fixed contact 531 and is blown onto the arc 60.

[0026] In this way, the arc 60 is quickly extinguished by the synergistic effect of the gas flow of insulating gas sucked into the first puffer chamber 571 and the gas flow of insulating gas ejected from the second puffer chamber 572, thereby interrupting the current.

[0027] Here, the guide member 58 is shaped to guide the gas flow so that the direction of the gas flow sucked into the first puffer chamber 571 bends from a direction intersecting the arc 60 to the axial direction of the movable contact 541, but the guide member 58 may also be shaped to change the direction of the gas flow sucked into the first puffer chamber 571 continuously or stepwise from a direction intersecting the arc 60 to the axial direction of the movable contact 541.

[0028] The ring portion 561 a is made of a material with a high melting point, such as tungsten, and is therefore unlikely to be damaged even when exposed to the arc 60 .

[0029] Since the earthing switch 50 according to the first embodiment includes the second puffer chamber 572, the amount of the insulating gas flow that intersects with the arc 60 in one break operation is greater than in an earthing switch that does not include the second puffer chamber 572. Furthermore, since the insulating gas is simultaneously drawn into the first puffer chamber 571 and blown from the second puffer chamber 572, the arc extinguishing performance is improved, and therefore there is no need to increase the size to satisfy the arc extinguishing performance. Note that if the arc 60 can be extinguished only by the gas flow of the insulating gas drawn into the first puffer chamber 571, the earthing switch 50 may be configured without the second puffer chamber 572.

[0030] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, or parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0031] 10 electric circuit, 20 disconnecting switch, 30 circuit breaker, 40 lightning arrester, 50 earthing switch, 51 tank, 52 electric circuit conductor, 53 fixed contact, 54 moving contact, 55 operating device, 58 guide member, 59 flange, 60 arc, 100 gas insulated switchgear, 531 fixed contact, 532 shield, 541 moving contact, 541a one end, 541b other end, 542 cylinder, 542a head portion, 542b, 542c, 563a seal, 543 anchor, 551 rod, 561 single cylinder portion, 561a ring portion, 561b support leg, 561c nut, 562 double cylinder portion, 562a inner cylinder, 562b outer cylinder, 562c hole, 563 piston, 565 connection portion, 567 Gas hole, 571 first puffer chamber, 572 second puffer chamber.

Claims

1. a fixed contact installed in a tank filled with insulating gas; a movable contact disposed in the tank so as to be movable between a closing position where the movable contact comes into contact with the fixed contact and a closing position where a gap exists between the movable contact and the fixed contact; an operating device that is installed outside the tank and causes the movable contact to perform a closing operation and a breaking operation, The fixed contact includes a fixed contact piece connected to an electrical path conductor; The movable contact includes a movable contact inserted into the fixed contact at the closing position and in contact with the fixed contact; a first puffer chamber into which the insulating gas in the tank flows through a hole formed in one end of the movable contactor that is closer to the fixed contactor during the breaking operation; and a second puffer chamber from which the insulating gas is ejected toward the fixed contactor during the breaking operation. a guide member that is installed at one end of the movable contactor so as to form a gap between the one end of the movable contactor and the guide member that faces the other end of the movable contactor more toward the other end of the movable contactor than in a direction perpendicular to the moving direction of the movable contactor, and that changes the gas flow of the insulating gas that flows into the first puffer chamber during the breaking operation from a flow in a direction inclined with respect to the central axis of the movable contactor so that the gas flow approaches the central axis of the movable contactor as it approaches the one end, to a flow along the central axis of the movable contactor. A grounding switch characterized by:

2. 2. The earthing switch according to claim 1, wherein the guide member is made of an insulating material.

3. The movable contact is connected to the movable contactor and a cylinder so as to be extendable and contractible. the movable contactor has a single cylindrical portion and a double cylindrical portion having an inner cylindrical portion and an outer cylindrical portion, the single cylindrical portion is connected to an end of the double cylindrical portion that is closer to the fixed contact, and the interior of the single cylindrical portion and the interior of the inner cylindrical portion are connected to form the first puffer chamber, a head portion is formed at an end of the cylinder closer to the fixed contact, the head portion being thicker than the other portion of the cylinder, and a gap is formed between the cylinder and the inner tube; a hole is formed in the inner cylinder, the hole connecting a portion of the space between the inner cylinder and the outer cylinder that is farther from the fixed contact than the head portion to the first puffer chamber; 3. The earthing switch according to claim 1, wherein a portion of the space between the inner cylinder and the outer cylinder that is closer to the fixed contact than the head portion forms the second puffer chamber.

4. A fixed contact installed in a tank filled with insulating gas; a movable contact disposed in the tank so as to be movable between a closing position where the movable contact comes into contact with the fixed contact and a closing position where a gap exists between the movable contact and the fixed contact; an operating device that is installed outside the tank and causes the movable contact to perform a closing operation and a breaking operation, The fixed contact includes a fixed contact piece connected to an electrical path conductor; The movable contact includes a movable contact inserted into the fixed contact at the closing position and in contact with the fixed contact; a first puffer chamber into which the insulating gas in the tank flows through a hole formed in one end of the movable contactor on a side closer to the fixed contactor during the breaking operation, and a second puffer chamber from which the insulating gas is ejected toward the fixed contactor during the breaking operation, The movable contact is connected to the movable contactor and a cylinder so as to be extendable and contractible. the movable contactor has a single cylindrical portion and a double cylindrical portion having an inner cylindrical portion and an outer cylindrical portion, the single cylindrical portion is connected to an end of the double cylindrical portion that is closer to the fixed contact, and the interior of the single cylindrical portion and the interior of the inner cylindrical portion are connected to form the first puffer chamber, a head portion is formed at an end of the cylinder closer to the fixed contact, the head portion being thicker than the other portion of the cylinder, and a gap is formed between the cylinder and the inner tube; a hole is formed in the inner cylinder, the hole connecting a portion of the space between the inner cylinder and the outer cylinder that is farther from the fixed contact than the head portion to the first puffer chamber; A grounding switch characterized in that a portion of the space between the inner cylinder and the outer cylinder that is closer to the fixed contact than the head portion forms the second puffer chamber.

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